462 resultados para Bay of Fundy


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Analysis of composition and distribution of benthic foraminifers in six samples of bottom sediments obtained in the southeast Kandalaksha Bay of the White Sea at water depths of 20 to 155 m revealed their dependence on lithology and different hydrological characteristics. It is shown that living foraminifers populating relatively shallow areas of the bay (20-60 m), which are bathed by seasonally warmed intermediate water with temperature 0.7-1.5°C and salinity 26 per mil, are characterized by high abundance (250-750 specimens/10 ccm of wet sediment) and prevalence of agglutinated species (Eggerella advena, Recurvoides turbinatus, and others). Deeper (155 m) where cold and relatively saline deep water occurs (-1.4°C, 29.5 per mil), abundance is an order lower (30 specimens/10 ccm) and is dominated by calcareous taxa Cassidulina reniforme, an Arctic cold resistant species.

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A complex study of influence of various environmental factors on rates of oxygen (M_O2 ), ammonium (M_NH4), and phosphate (M_PO4) metabolism in Ahnfeltia tobuchiensis has been carried out in situ in the Izmena Bay of the Kunashir Island. The following environmental factors have been included into the investigation: photosynthetically active radiation (PAR); ammonium (NH4); phosphate (PO4); and contents of carbon (C), nitrogen (N), phosphorus (P), and chlorophyll a (Chl) in tissue. Population of agar-containing seaweed A. tobuchiensis forms a layer with thickness up to 0.5 m, which occupies about 23.3 km**2; biomass is equal to 125000 tons. Quantitative assessment of organic matter production and nutrient consumption during oxygen metabolism has been carried out for the whole population. It has been shown that daily oxygen metabolism depends on PAR intensity, concentrations of PO4 and NH4 in seawater, and contents of N and P in tissues (r**2=0.78, p<0.001). Average daily NH4 consumption is 0.21 µmol/g of dry weight/hour and depends on NH4 and O2 concentrations in seawater and on ? and Chl a contents in algal tissues (r**2=0.64, p<0.001). Average daily PO4 consumption is 0.01 µmol/g of dry weight/hour and depends on NH4 concentrations in seawater and on P contents in algal tissues (r**2=0.40, p<0.001).

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Data on distribution of zoobenthos in the Kemskaya Guba (or Kemskaya Bay - the estuary of the Kem' River entering the Onega Bay of the White Sea), which is strongly influenced by river runoff, are presented. The number of species at sampling stations varied from 4 to 65. Density of communities and zoobenthos biomass varied from 342±68 to 4293±96 #/m**2 and from 0.418±0.081 to 1975.22±494.36 g/m**2, respectively. Shannon index values varied between 1.19 to 4.7 bit/ind. At the upper part of the estuary, detritivores dominated, while in the central part and at outlets sestonophages prevailed. Changes in quantitative parameters of the zoobenthos along gradient of water salinity were traced, and relations of these parameters with seven other environmental factors were revealed. It was found that species composition, biodiversity, and trophic structure of the zoobenthos significantly correlated with some of parameters mentioned above. Multiple regression analysis was used to assess combined effect of factors, and it revealed which of them played a determining role in Kemskaya Guba: for species composition - depth, water color, and total concentration of suspended matter; for number of species - contents of <0.01 mm grain size (pelite) fraction and organic carbon in bottom sediments. Biomass depended on water salinity, water chromaticity, and organic carbon contents in bottom sediments and suspended matter. Values of the Shannon index of diversity are determined by water color, and contents of organic carbon and pelite fraction in bottom sediments. Calculations of ecological stress values revealed two zones with unstable state of the zoobenthos.

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Distributions of dissolved oxygen concentration, pH, and concentrations of dissolved silica, phosphates, strontium, calcium, fluorine, and boron in mouth areas of small rivers (Niva, Kolvitsa, Knyazhaya, and Keret') entering Kandalaksha Bay of the White Sea were studied. Strontium, calcium, fluorine, and boron showed conservative, silica and phosphates showed non-conservative behavior caused by their biological consumption.